This invention relates to a fastener assembly of the type which is molded into foam structures, such as seat cushions. The fastener assembly according to the particular embodiment disclosed in this application cooperates with a complementary fastener assembly on an upholstery cover to hold the cover in place on the cushion. Hook and loop-type fasteners are a common type of fastener assembly used for this application.
Prior art patents in this field include Applicant's U.S. Pat. Nos. 4,693,921, 4,802,939, and 4,933,035. These patents disclose the provision of a thin plastic film which covers the attachment hooks to prevent intrusion of liquid foam into the area of the hooks during molding. Thus, the hooks do not become contaminated during molding and maintain their full ability to cooperate with the loops on the cover to keep the cover in place on the cushion. The film provides excellent protection against foam intrusion but must be removed from over the hooks after molding is complete according to one of several methods. Applicant has also employed metal shim stock material secured to the film and extending along the center of the fastener to hold the fastener in a mold having magnets.
U.S. Pat. No. 4,784,890 ('890 Patent) discloses a fastener which does not have an overlying plastic film covering the hooks, but relies on magnets to seal the fastener into the mold recess along the sides. The ends of the fastener are held in the mold recess by "restricting means", disclosed in the alternative as a length of polymeric film attached to and extending beyond the end of the fastener to be held in place by magnets in the mold, Col. 4, line 58-Col. 5, line 2; or "dam-like structures" which are placed on the ends of the fastener where the hooks have been removed by melting or cutting away the hooks to provide a flat area. Col. 5, lines 2-13. In the '890 Patent the magnetic material for protecting the ends is attached as a short tab to the end of the fastener and extends beyond the end of the fastener and over the marginal edge portions.
The present invention provides an efficient and inexpensive fastener which can be used without a protective film, and which does not require attachment of hold-down members which extend beyond the ends of the fastener.